Quantitative Precipitation Forecast
Issued by NWS

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000
FOUS30 KWBC 250753
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
352 AM EDT THU JUN 25 2015

...VALID 12Z THU JUN 25 2015 - 12Z FRI JUN 26 2015...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
25 ENE W99 30 SE 48I 25 N I16 40 NW HTS 25 WNW SDF OLY 10 E STL
20 E AIZ 45 S SZL 20 WNW FOE 25 ESE HJH 10 SW AFK 20 NW IRK
10 E DEC 15 NNW MIE 10 N HLG 30 W CXY WRI 50 ESE ACY 50 ESE OXB
10 NNW WAL IAD 25 ENE W99.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
35 N BFF 40 SSW CUT 45 ESE BFU 15 SSW GCC 15 N GCC 30 NNW IKA
35 NNW RCA 20 WSW PHP 50 NW VTN 25 E IEN 30 S IEN AIA 20 W AIA
35 N BFF.


...MID MISSISSIPPI VALLEY EAST TO THE MID ATLANTIC REGION...

IN THE SHORT TERM (THROUGH 18Z THU)...MCS AND EVOLVING MCV ACROSS
THE MID MS VLY EARLY WILL CONTINUE AN ESE TRACK ALONG THE LOW-MID
LEVEL THERMAL GRADIENT. WHILE EXPECT THE TYPICAL DISSIPATING TREND
AFTER SUNRISE (PER THE WEAKENING LLJ)...SCATTERED-NUMEROUS
CONVECTIVE ORGANIZATION WILL CONTINUE INTO THE MID ATLC REGION BY
LATE AFTN AND WELL INTO THE EVENING WITH THE DIURNAL
DESTABILIZATION...MOISTURE FLUX CONVERGENCE ALONG THE LOW-LEVEL
FRONT...AND ENHANCED DYNAMICAL SUPPORT (UPPER DIVERGENCE...LOW-MID
LEVEL FGEN) VIA THE RIGHT ENTRANCE REGION OF THE JET STREAK ACROSS
SOUTHERN NEW ENGLAND. GENERALLY FOLLOWED THE WRF-ARW AND ITS
PARALLEL VERSION IN TERMS OF THE TIMING/TRACK OF THE MCS EARLY
TODAY...PARTICULARLY WITH THE HIGHER QPF CLOSER TO THE SFC BNDRY
AND TOWARD THE AXIS OF MAXIMUM INSTABILITY/MIXED-LAYER CAPE. ALL
THE OTHER GUIDANCE (INCLUDING THE HRRR) HAS BEEN CONSISTENTLY TOO
FAR NORTH. ALSO LEANED TOWARD THE WRF-ARW WITH THE NEXT MCS
OVERNIGHT...WITH THE MAX QPF CENTERED ACROSS NORTHERN-CENTRAL MO
(CONTINUING A SW-S TREND FROM THE PREVIOUS NIGHT). MAXIMUM
AREAL-AVERAGE QPF OF 2-3+ INCHES IS NOTED ACROSS THE MID MS VLY
DURING THE DAY 1 PERIOD (ASSOCIATED WITH THE CURRENT MCS AND
ANTICIPATED ONE OVERNIGHT)...OTHERWISE A STRIPE OF GENERALLY
0.50-1.50 INCH AMOUNTS ARE NOTED W-E FROM THE CENTRAL/SRN IN/OH
INTO THE NORTHERN MID ATLC REGION (WITH LOWER AREAL-AVERAGE TOTALS
EAST OF THE CENTRAL APPALACHIANS WITH THE DOWNSLOPING LOW-LEVEL
FLOW).

OUTSIDE OF THE HEAVY RAINFALL ASSOCIATED WITH THE MCS EARLY TODAY
AND THE ANTICIPATED MCS OVERNIGHT INTO EARLY FRI OVER THE MID MS
VLY...WHERE THE MESOSCALE GUIDANCE SHOWS ISOLATED TOTALS BETWEEN
4-6+ INCHES...THE POTENTIAL FOR EXCESSIVE RAINFALL WILL BE
ELEVATED ALONG THE AFOREMENTIONED FRONTAL BOUNDARY AND AXIS OF
MAXIMUM QPF EAST TOWARD THE NORTHERN MID ATLANTIC COAST. PER SOME
OF THE MESOSCALE GUIDANCE...LOCAL AMOUNTS OF 3-4+ INCHES ARE
POSSIBLE WITHIN THIS ZONE EAST OF THE MID MS VALLEY...WHICH WOULD
BE MOST PROBLEMATIC ACROSS WV INTO PORTIONS OF CENTRAL/SOUTHERN MD
WHERE THE LATEST 3-HOURLY FFG IS ONLY AROUND 1" IN ISOLATED AREAS.



...HIGH PLAINS OF WYOMING / SOUTH DAKOTA AND ADJACENT STATES...

ANOTHER LOW-AMPLITUDE NORTHERN STREAM SHORTWAVE WILL APPROACH
EARLY THIS MORNING...WHICH WITH THE ACCOMPANYING MODERATE
MID-LEVEL FORCING...ANOMALOUS MOISTURE (PWS 2-2.5 STANDARD
DEVIATIONS ABOVE NORMAL)...FAVORABLE DEEP LAYER INSTABILITY
(MIXED-LAYER CAPES ~1000 J/KG EARLY INCREASING TO 1500-2000 J/KG
LATER TODAY)...AND STRENGTHENING E-SE UPSLOPE LOW-LEVEL FLOW WILL
BE MORE THAN SUFFICIENT FOR ADDITIONAL ROUNDS OF ORGANIZED
CLUSTERED CONVECTION WITH AREAS OF HEAVY (POTENTIALLY EXCESSIVE)
RAINFALL. AUGMENTING THE EXCESSIVE RAINFALL THREAT WILL BE THE
ENHANCED E-SE LOW LEVEL INFLOW OPPOSING THE W-WNW 850-300 MB MEAN
FLOW...WHICH WILL ALLOW FOR TRAINING OF CELLS OVER THE SAME AREA.

HURLEY
$$





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